// pages/sign-name/sign-name.js
Page({
  /**
   * 页面的初始数据
   */
  data: {
    canvasName: "signCanvas",
    ctx: "", // 上下文实例
    canvas: "", // 画布实例
    canvasWidth: 0,
    canvasHeight: 0,
    transparent: 1, // 透明度
    selectColor: "black",
    lineColor: "#1A1A1A", // 颜色
    lineSize: 1.5, // 笔记倍数
    lineMin: 0.5, // 最小笔画半径
    lineMax: 4, // 最大笔画半径
    pressure: 1, // 默认压力
    smoothness: 60, //顺滑度，用60的距离来计算速度
    currentPoint: {},
    currentLine: [], // 当前线条
    firstTouch: true, // 第一次触发
    radius: 1, //画圆的半径
    cutArea: { top: 0, right: 0, bottom: 0, left: 0 }, //裁剪区域
    bethelPoint: [], //保存所有线条 生成的贝塞尔点；
    lastPoint: 0,
    chirography: [], //笔迹
    currentChirography: {}, //当前笔迹
    linePrack: [], //划线轨迹 , 生成线条的实际点
    isDraw: false, // 判断用户是否绘制
    upPageNumber: 0,
    offCanvas: "",
    offCtx: "",
    dpr: "",
  },

  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function (options) {
    this.createSignature();
  },

  createSignature() {
    if (!this.signature) {
      this.signature = this.selectComponent("#signature");
    }
  },

  /**
   * 生命周期函数--监听页面初次渲染完成
   */
  onReady: function () {},

  /**
   * 生命周期函数--监听页面显示
   */
  onShow: function () {},

  // 重写事件(初始化画布)
  retDraw() {
    this.signature.clear();
  },
  // 完成事件
  async subCanvas() {
    const res = await this.signature.getCanvasImg();
    console.log("res", res);
  },

  //画两点之间的线条；参数为:line，会绘制最近的开始的两个点；
  pointToLine(line) {
    this.calcBethelLine(line);
    return;
  },
  // 笔迹开始
  uploadScaleStart(e) {
    if (e.type != "touchstart") return false;
    let ctx = this.data.ctx;
    ctx.fillStyle = this.data.lineColor; // 初始线条设置颜色
    ctx.globalAlpha = this.data.transparent; // 设置半透明
    let currentPoint = {
      x: e.touches[0].x,
      y: e.touches[0].y,
    };
    let currentLine = this.data.currentLine;
    currentLine.unshift({
      time: new Date().getTime(),
      dis: 0,
      x: currentPoint.x,
      y: currentPoint.y,
    });
    this.setData({
      currentPoint,
      // currentLine
    });
    if (this.data.firstTouch) {
      this.setData({
        cutArea: {
          top: currentPoint.y,
          right: currentPoint.x,
          bottom: currentPoint.y,
          left: currentPoint.x,
        },
        firstTouch: false,
      });
    }
    this.pointToLine(currentLine);
  },
  // 笔迹移动
  uploadScaleMove(e) {
    if (e.type != "touchmove") return false;
    if (e.cancelable) {
      // 判断默认行为是否已经被禁用
      if (!e.defaultPrevented) {
        e.preventDefault();
      }
    }
    let point = {
      x: e.touches[0].x,
      y: e.touches[0].y,
    };

    //测试裁剪
    if (point.y < this.data.cutArea.top) {
      this.data.cutArea.top = point.y;
    }
    if (point.y < 0) this.data.cutArea.top = 0;

    if (point.x > this.data.cutArea.right) {
      this.data.cutArea.right = point.x;
    }
    if (this.data.canvasWidth - point.x <= 0) {
      this.data.cutArea.right = this.data.canvasWidth;
    }
    if (point.y > this.data.cutArea.bottom) {
      this.data.cutArea.bottom = point.y;
    }
    if (this.data.canvasHeight - point.y <= 0) {
      this.data.cutArea.bottom = this.data.canvasHeight;
    }
    if (point.x < this.data.cutArea.left) {
      this.data.cutArea.left = point.x;
    }
    if (point.x < 0) this.data.cutArea.left = 0;

    this.setData({
      lastPoint: this.data.currentPoint,
      currentPoint: point,
    });
    let currentLine = this.data.currentLine;
    currentLine.unshift({
      time: new Date().getTime(),
      dis: this.distance(this.data.currentPoint, this.data.lastPoint),
      x: point.x,
      y: point.y,
    });
    // this.setData({
    //   currentLine
    // })
    this.pointToLine(currentLine);
  },
  // 笔迹结束
  uploadScaleEnd(e) {
    if (e.type != "touchend") return 0;
    let point = {
      x: e.changedTouches[0].x,
      y: e.changedTouches[0].y,
    };
    this.setData({
      lastPoint: this.data.currentPoint,
      currentPoint: point,
    });
    let currentLine = this.data.currentLine;
    currentLine.unshift({
      time: new Date().getTime(),
      dis: this.distance(this.data.currentPoint, this.data.lastPoint),
      x: point.x,
      y: point.y,
    });
    // this.setData({
    //   currentLine
    // })
    if (currentLine.length > 2) {
      var info =
        (currentLine[0].time - currentLine[currentLine.length - 1].time) /
        currentLine.length;
      //$("#info").text(info.toFixed(2));
    }
    //一笔结束，保存笔迹的坐标点，清空，当前笔迹
    //增加判断是否在手写区域；
    this.pointToLine(currentLine);
    var currentChirography = {
      lineSize: this.data.lineSize,
      lineColor: this.data.lineColor,
    };
    var chirography = this.data.chirography;
    chirography.unshift(currentChirography);
    this.setData({
      chirography,
    });
    var linePrack = this.data.linePrack;
    linePrack.unshift(this.data.currentLine);
    this.setData({
      linePrack,
      currentLine: [],
    });
    this.data.isDraw = true;
  },

  //计算插值的方式；
  calcBethelLine(line) {
    if (line.length <= 1) {
      line[0].r = this.data.radius;
      return;
    }
    let x0,
      x1,
      x2,
      y0,
      y1,
      y2,
      r0,
      r1,
      r2,
      len,
      lastRadius,
      dis = 0,
      time = 0,
      curveValue = 0.5;
    if (line.length <= 2) {
      x0 = line[1].x;
      y0 = line[1].y;
      x2 = line[1].x + (line[0].x - line[1].x) * curveValue;
      y2 = line[1].y + (line[0].y - line[1].y) * curveValue;
      //x2 = line[1].x;
      //y2 = line[1].y;
      x1 = x0 + (x2 - x0) * curveValue;
      y1 = y0 + (y2 - y0) * curveValue;
    } else {
      x0 = line[2].x + (line[1].x - line[2].x) * curveValue;
      y0 = line[2].y + (line[1].y - line[2].y) * curveValue;
      x1 = line[1].x;
      y1 = line[1].y;
      x2 = x1 + (line[0].x - x1) * curveValue;
      y2 = y1 + (line[0].y - y1) * curveValue;
    }
    //从计算公式看，三个点分别是(x0,y0),(x1,y1),(x2,y2) ；(x1,y1)这个是控制点，控制点不会落在曲线上；实际上，这个点还会手写获取的实际点，却落在曲线上
    len = this.distance({ x: x2, y: y2 }, { x: x0, y: y0 });
    lastRadius = this.data.radius;
    for (let n = 0; n < line.length - 1; n++) {
      dis += line[n].dis;
      time += line[n].time - line[n + 1].time;
      if (dis > this.data.smoothness) break;
    }
    this.setData({
      radius:
        Math.min(
          (time / len) * this.data.pressure + this.data.lineMin,
          this.data.lineMax
        ) * this.data.lineSize,
    });
    line[0].r = this.data.radius;
    //计算笔迹半径；
    if (line.length <= 2) {
      r0 = (lastRadius + this.data.radius) / 2;
      r1 = r0;
      r2 = r1;
      //return;
    } else {
      r0 = (line[2].r + line[1].r) / 2;
      r1 = line[1].r;
      r2 = (line[1].r + line[0].r) / 2;
    }
    let n = 5;
    let point = [];
    for (let i = 0; i < n; i++) {
      let t = i / (n - 1);
      let x = (1 - t) * (1 - t) * x0 + 2 * t * (1 - t) * x1 + t * t * x2;
      let y = (1 - t) * (1 - t) * y0 + 2 * t * (1 - t) * y1 + t * t * y2;
      let r = lastRadius + ((this.data.radius - lastRadius) / n) * i;
      point.push({ x: x, y: y, r: r });
      if (point.length == 3) {
        let a = this.ctaCalc(
          point[0].x,
          point[0].y,
          point[0].r,
          point[1].x,
          point[1].y,
          point[1].r,
          point[2].x,
          point[2].y,
          point[2].r
        );
        a[0].color = this.data.lineColor;
        // let bethelPoint = this.data.bethelPoint;
        // console.log(a)
        // console.log(this.data.bethelPoint)
        // bethelPoint = bethelPoint.push(a);
        this.bethelDraw(a, 1);
        point = [{ x: x, y: y, r: r }];
      }
    }
    this.setData({
      currentLine: line,
    });
  },
  //求两点之间距离
  distance(a, b) {
    let x = b.x - a.x;
    let y = b.y - a.y;
    return Math.sqrt(x * x + y * y);
  },
  ctaCalc(x0, y0, r0, x1, y1, r1, x2, y2, r2) {
    let a = [],
      vx01,
      vy01,
      norm,
      n_x0,
      n_y0,
      vx21,
      vy21,
      n_x2,
      n_y2;
    vx01 = x1 - x0;
    vy01 = y1 - y0;
    norm = Math.sqrt(vx01 * vx01 + vy01 * vy01 + 0.0001) * 2;
    vx01 = (vx01 / norm) * r0;
    vy01 = (vy01 / norm) * r0;
    n_x0 = vy01;
    n_y0 = -vx01;
    vx21 = x1 - x2;
    vy21 = y1 - y2;
    norm = Math.sqrt(vx21 * vx21 + vy21 * vy21 + 0.0001) * 2;
    vx21 = (vx21 / norm) * r2;
    vy21 = (vy21 / norm) * r2;
    n_x2 = -vy21;
    n_y2 = vx21;
    a.push({ mx: x0 + n_x0, my: y0 + n_y0, color: "#1A1A1A" });
    a.push({
      c1x: x1 + n_x0,
      c1y: y1 + n_y0,
      c2x: x1 + n_x2,
      c2y: y1 + n_y2,
      ex: x2 + n_x2,
      ey: y2 + n_y2,
    });
    a.push({
      c1x: x2 + n_x2 - vx21,
      c1y: y2 + n_y2 - vy21,
      c2x: x2 - n_x2 - vx21,
      c2y: y2 - n_y2 - vy21,
      ex: x2 - n_x2,
      ey: y2 - n_y2,
    });
    a.push({
      c1x: x1 - n_x2,
      c1y: y1 - n_y2,
      c2x: x1 - n_x0,
      c2y: y1 - n_y0,
      ex: x0 - n_x0,
      ey: y0 - n_y0,
    });
    a.push({
      c1x: x0 - n_x0 - vx01,
      c1y: y0 - n_y0 - vy01,
      c2x: x0 + n_x0 - vx01,
      c2y: y0 + n_y0 - vy01,
      ex: x0 + n_x0,
      ey: y0 + n_y0,
    });
    a[0].mx = a[0].mx.toFixed(1);
    a[0].mx = parseFloat(a[0].mx);
    a[0].my = a[0].my.toFixed(1);
    a[0].my = parseFloat(a[0].my);
    for (let i = 1; i < a.length; i++) {
      a[i].c1x = a[i].c1x.toFixed(1);
      a[i].c1x = parseFloat(a[i].c1x);
      a[i].c1y = a[i].c1y.toFixed(1);
      a[i].c1y = parseFloat(a[i].c1y);
      a[i].c2x = a[i].c2x.toFixed(1);
      a[i].c2x = parseFloat(a[i].c2x);
      a[i].c2y = a[i].c2y.toFixed(1);
      a[i].c2y = parseFloat(a[i].c2y);
      a[i].ex = a[i].ex.toFixed(1);
      a[i].ex = parseFloat(a[i].ex);
      a[i].ey = a[i].ey.toFixed(1);
      a[i].ey = parseFloat(a[i].ey);
    }
    return a;
  },
  bethelDraw(point, is_fill, color) {
    let ctx = this.data.ctx;
    ctx.beginPath();
    ctx.moveTo(point[0].mx, point[0].my);
    if (undefined != color) {
      ctx.fillStyle = color;
      ctx.strokeStyle = color;
    } else {
      ctx.fillStyle = point[0].color;
      ctx.strokeStyle = point[0].color;
    }
    for (let i = 1; i < point.length; i++) {
      ctx.bezierCurveTo(
        point[i].c1x,
        point[i].c1y,
        point[i].c2x,
        point[i].c2y,
        point[i].ex,
        point[i].ey
      );
    }
    ctx.stroke();
    if (undefined != is_fill) {
      ctx.fill(); //填充图形 ( 后绘制的图形会覆盖前面的图形, 绘制时注意先后顺序 )
    }
  },
  //设置canvas背景色  不设置  导出的canvas的背景为透明
  //@params：字符串  color
  setCanvasBg(color) {
    console.log("开始设置背景色");
    /* 将canvas背景设置为 白底，不设置  导出的canvas的背景为透明 */
    //rect() 参数说明  矩形路径左上角的横坐标，左上角的纵坐标, 矩形路径的宽度, 矩形路径的高度
    //这里是 canvasHeight - 4 是因为下边盖住边框了，所以手动减了写
    this.data.ctx.rect(0, 0, this.data.canvasWidth, this.data.canvasHeight - 4);
    this.data.ctx.fillStyle = color;
    this.data.ctx.fill(); //设置填充
  },
  //预览
  async previewCanvasImg() {
    this.data.offCtx.rotate((-90 * Math.PI) / 180);
    // offCtx.clearRect(0, 0, 100, 100)
    const srcImg = this.data.offCanvas.createImage();
    console.log("srcImg", srcImg);
    // 等待图片加载
    // console.log(this.data.canvas.toDataURL('image/png', 1))
    await new Promise((resolve) => {
      srcImg.onload = resolve;
      srcImg.src = this.data.canvas.toDataURL("image/png", 1); // 要加载的图片 url
    });
    let width = this.data.canvasWidth / this.data.dpr;
    let height = this.data.canvasHeight / this.data.dpr;
    this.data.offCtx.drawImage(srcImg, -width, 0, width, height);
    wx.canvasToTempFilePath({
      canvas: this.data.offCtx,
      fileType: "jpg",
      quality: 1, //图片质量
      success(res) {
        console.log(res.tempFilePath, "canvas生成图片地址");

        wx.previewImage({
          urls: [res.tempFilePath], //预览图片 数组
        });
      },
      fail(err) {
        console.log(err, "失败");
      },
    });
  },
  //上传
  async uploadCanvasImg() {
    if (!this.data.isDraw) {
      wx.showToast({
        title: "请签名",
        icon: "error",
      });
      return;
    }
    // console.log('===============')
    const self = this;
    this.data.offCtx.rotate((-90 * Math.PI) / 180);
    // offCtx.clearRect(0, 0, 100, 100)
    const srcImg = this.data.offCanvas.createImage();
    // 等待图片加载
    // console.log(this.data.canvas.toDataURL('image/png', 1))
    await new Promise((resolve) => {
      srcImg.onload = resolve;
      srcImg.src = this.data.canvas.toDataURL("image/png", 1); // 要加载的图片 url
      console.log("await============");
    });
    console.log("await0============");
    console.log(srcImg);
    let width = this.data.canvasWidth / this.data.dpr;
    let height = this.data.canvasHeight / this.data.dpr;
    this.data.offCtx.drawImage(srcImg, -width, 0, width, height);
    console.log("===============2");
    console.log(srcImg);
    wx.canvasToTempFilePath({
      canvas: this.data.offCanvas,
      fileType: "jpg", // png默认无背景是透明的，可以改jpg
      quality: 1, //图片质量
      success(res) {
        console.log("res", res);
      },
      fail(res) {
        console.log(res);
      },
    });
  },
});
